TRANSPARENT ALUMINA CERAMICS WITH ORIENTED GRAINS AND PREPARATION METHOD THEREOF

• US 20110039685A1
• Filed: 06/28/2010
• Published: 02/17/2011
• Est. Priority Date: 12/26/2007
• Status: Abandoned Application

• Current Assignee: Shanghai Institute Of Ceramics, Chinese Academy Of Sciences (Chinese Academy of Sciences)
• Original Assignee: Shanghai Institute Of Ceramics, Chinese Academy Of Sciences (Chinese Academy of Sciences)
• Inventors: SHIMAI, Shunzo, MAO, Xiaojian, WANG, Shiwei
• Application Number:
  US12/824,776
• Publication Number:
  US 20110039685A1
• Time in Patent Office: Days
• US Class Current: 501/153
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3241 Chromium oxides, chromates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/443 Nitrates or nitrites
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/602 Making the green bodies or pre-forms by moulding
• CPC Class Codes: C04B 2235/6023 Gel casting
• CPC Class Codes: C04B 2235/6027 Slip casting
• CPC Class Codes: C04B 2235/605 Making or treating the green body or pre-form in a magnetic field
• CPC Class Codes: C04B 2235/6582 Hydrogen containing atmosphere
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/787 Oriented grains
• CPC Class Codes: C04B 2235/9661 Colour
• CPC Class Codes: C04B 35/115 Translucent or transparent products
• CPC Class Codes: C04B 35/6263 characterised by their solids loadings, i.e. the percentage of solids
• CPC Class Codes: C04B 35/63424 Polyacrylates; Polymethacrylates
• CPC Class Codes: C04B 35/6455 Hot isostatic pressing

Abstract

A kind of transparent alumina ceramics is disclosed herein, the optical axes of all or part of the crystal grains of the transparent alumina ceramics are arranged in a direction, which makes the transparent alumina ceramics have orientation.

Claims

1. A kind of transparent alumina ceramics, wherein the optical axes of all or part of the crystal grains of the transparent alumina ceramics are arranged in a direction.

2. The transparent alumina ceramics of claim 1, wherein the arrangement of the optical axes is achieved by a magnetic field which is stronger than 1 T.

3. The transparent alumina ceramics of claim 2, wherein the strong magnetic field is or 10-30 T.

4. The transparent alumina ceramics of claim 2, wherein the strong magnetic field is of 10-20 T.

5. The transparent alumina ceramics of claim 2, wherein for the cross section perpendicular to the magnetic field, the diffraction peak of (006) crystal plane is remarkably enhanced, while no diffraction peak of (110) crystal plane appears.

6. The transparent alumina ceramics of claim 5, wherein the diffraction peak of (006) has an intensity of 20 times greater than that of (110) crystal plane or (300) crystal plane.

7. The transparent alumina ceramics of claim 5, wherein at least 60% of the crystal grains has optical extinction simultaneously.

8. The transparent alumina ceramics of claim 5, wherein it further contains doped Cr or Ti ions.

9. The preparation method of the transparent alumina ceramics of claim 1, wherein comprises of following steps:

a) Providing a slurry of dispersed alumina containing optional sintering aid and optional dispersant,

b) Casting and Shaping the slurry of step a) in a strong magnetic field no lower than 1 T, to arrange alumina particles in terms of c axes parallel to the magnetic field direction, and to obtain oriented bodies,

c) De-molding the oriented bodies of step b) and calcining in air at 600-1200°

C.,

d) Sinstering the calcined bodies of step c) in hydrogen at 1700-1950°

C. to obtain the transparent alumina ceramics.

10. The method of claim 9, wherein the bodies of step c) is calcined at 800-1200°

C.

11. The method of claim 9, wherein the calcined bodies in step d) is fired at 1750-1900°

C.

12. The method of claim 9, wherein the sintering aid is MgO.

13. The method of claim 9, wherein the dispersant is ammonium polyacrylate.

14. The method of claim 9, wherein the molding method is one or slip casting, pressure casting, gel-casting, or electrophoretic deposition.

15. The usage of the transparent alumina ceramics of claim 1, wherein it functioned as optical lenses, transparent windows.

16. The usage of the transparent alumina ceramics of claim 1, wherein the polycrystalline alumina ceramics doped with Cr or Ti ions functioned as laser media materials or scintillating media materials.

17. A kind of laser ceramic article prepared from the transparent alumina ceramics of claim 1.